1. Field of the Invention
The present invention relates to a double-sided printing device and method, an image forming apparatus and a control method therefor, and a storage medium, and more particularly, a double-sided printing device and method which can perform double sided printing on a sheet, as well as an image forming apparatus incorporating the double-sided printing device and a control method therefor, and a storage medium containing a program for implementing the control method.
2. Description of the Related Art
In recent years, among image forming apparatuses such as copying machines, a copying machine having a printed recording sheet discharge outlet inside the housing of an image output device thereof has been developed to minimize the space occupied by the machine when it is installed.
Digital copying machines have come to additionally possess a printer function to serve as an output device for computers, and when this printer function as an output device for computers is performed, a printed recording sheet is discharged with the output side surface facing downward (output face-down sheet discharge). On the other hand, conventional copying machines perform discharge of a printed recording sheet with the output side surface facing upward (output face-up sheet discharge). In a copying machine that has a sheet discharge outlet inside the housing of an image output device thereof, although it is desirable that an inverted discharge unit be connected for switching between output face-down sheet discharge and output face-up sheet discharge so that both output face-down sheet discharge and output face-up sheet discharge are implemented, this is difficult to realize because of the occupied space.
If double-sided printing of recording sheets is performed by incorporating a double-sided printing device into an image forming apparatus capable of performing output face-down sheet discharge alone as described above, the sheets can be printed in proper order by first printing on the reverse surface, and then printing on the front or obverse surface, and discharging the printed recording sheet through output face-down sheet discharge.
However, there is a problem that, when a double-sided sheet, such as preprinted paper, is printed on the both surfaces by a double-sided printing device, if the sheet is set with an obverse surface thereof facing upward to be printed on one side surface thereof, the reverse surface image is printed on the obverse surface of the recording sheet.
It is an object of the present invention to provide a double-sided printing device and method that can eliminate a user having to care about the orientation of double-sided recording sheets when such recording sheets are set, as well as an image forming apparatus incorporating the double-sided printing device and a control method therefor, and a storage medium containing a program for implementing the control method.
To attain the above object, in a first aspect of the present invention, there is provided a double-sided printing device comprising at least one feed cassette, designating means for designating a type of a recording sheet to be fed from the feed cassette, the recording sheet having an obverse surface and a reverse surface, and printing means for printing an obverse surface image and a reverse surface image respectively on the obverse surface and the reverse surface of the recording sheet in a predetermined order, wherein the printing means reverses the predetermined order when the designated type of the recording sheet matches a predetermined type of recording sheet.
To attain the above object, the first aspect of the present invention also provides a double-sided printing method comprising the steps of designating a type of a recording sheet to be fed from at least one feed cassette of a double-sided printing device, and printing an obverse surface image and a reverse surface image respectively on the obverse surface and the reverse surface of the recording sheet in a predetermined order, wherein when the designated type of recording sheet matches a predetermined type of recording sheet, the predetermined order is reversed in the printing step.
According to the present invention, since a predetermined order in which an obverse surface image and a reverse surface image are printed, respectively, on the obverse surface and reverse surface of a recording sheet is reversed when a designated sheet type matches with a predetermined sheet type, the obverse surface image can be printed on the obverse surface of the recording sheet without fail, regardless of whether it is single-sided printing or double-sided printing, by setting a double-sided recording sheet with the obverse surface facing downward, thereby eliminating a user having to care about the orientation of a recording sheet when a double-sided recording sheet is set.
Preferably, the predetermined order is first the reverse surface and then the obverse surface.
Preferably, the printing means comprises disabling means for disabling printing on the obverse surface of the recording sheet.
More preferably, the printing means further comprises speed changing means operable when the disabling means disables printing on the obverse surface of the recording sheet, for increasing a conveyance speed of the recording sheet.
Also preferably the double-sided printing device comprises a fixing section having a heater, and wherein the printing means further comprises turning-off means operable when the disabling means disables printing on the obverse surface of the recording sheet, for turning off the heater of the fixing section.
Preferably, the at least one feed cassette comprises a plurality of feed cassettes for feeding respective different types of recording sheets including the predetermined type of recording sheet, and wherein the double-sided printing device comprises selecting means for selecting a feed cassette from the plurality of feed cassettes, and the selecting means does not select a feed cassette which feeds the predetermined type of recording sheet.
Typically, the recording sheet comprises at least one type of recording sheet selected from the group consisting of plain paper, recycled paper, thick paper, mother print paper, OHP paper, colored paper, prepunched paper, preprinted paper, letterhead, and label paper, and the predetermined type of recording sheet comprises at least one type of recording sheet selected from the group consisting of prepunched paper, preprinted paper, letterhead, and label paper.
Advantageously, the double-sided printing device is incorporated in a digital copying machine.
To attain the above object, in a second aspect of the present invention, there is provided an image forming apparatus capable of performing a double-sided printing process for printing a (2Nxe2x88x921)-th page image and a 2N-th page image of a print job of a plurality of pages on a first surface and a second surface of a sheet, comprising control means for controlling a double-sided printing mode operation to be executed such that the 2N-th page image is printed on the second surface of the sheet and the (2Nxe2x88x921)-th page image is printed on the first surface of the sheet.
Preferably, the control means controls the double-sided printing mode operation and a second double-sided printing mode operation different from the double-sided printing mode operation to be selectively executed.
More preferably, the second double-sided printing mode operation is executed such that the 2N-th page image is printed on the first surface of the sheet and the (2Nxe2x88x921)-th page image is printed on the second surface of the sheet.
Preferably, the control means determines which of the double-sided printing mode operation and the second double-sided printing mode operation is to be executed, based on a type of the sheet on which images of the print job are to be printed.
Specifically, it is preferable that the control means provides control such that when the type of the sheet on which images of the print job are to be printed is a predetermined type, the double-sided printing mode operation is executed, and when the type of the sheet on which images of the print job are to be printed is a type other than the predetermined type, the second double-sided printing mode operation is executed.
Typically, the type other than the predetermined type includes plain paper.
Preferably, the predetermined type includes at least one of prepunched paper and preprinted paper.
To attain the above object, the second aspect of the present invention also provides a method of controlling an image forming apparatus capable of performing a double-sided printing process for printing a (2Nxe2x88x921)-th page image and a 2N-th page image of a print job of a plurality of pages on a first surface and a second surface of a sheet, comprising a control step of controlling a double-sided printing mode operation to be executed such that the 2N-th page image is printed on the second surface of the sheet and the (2Nxe2x88x921)-th page image is printed on the first surface of the sheet.
To attain the above object, the second aspect of the present invention also provides a computer-readable storage medium storing a program for causing an image forming apparatus capable of performing a double-sided printing process for printing a (2Nxe2x88x921)-th page image and a 2N-th page image of a print job of a plurality of pages on a first surface and a second surface of a sheet to execute a control step of controlling a double-sided printing mode operation to be executed such that the 2N-th page image is printed on the second surface of the sheet and the (2Nxe2x88x921)-th page image is printed on the first surface of the sheet.
The above and other objects, features, and advantages of the invention will become more apparent from the following detailed description taken in connection with the accompanying with drawings.